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1.
Rosa María Agra Elvis Teijeira-Fernández Domingo Pascual-Figal Sánchez-Más Jesús Ángel Fernández-Trasancos Juan Sierra José Ramón González-Juanatey Sonia Eiras 《Life sciences》2014
Aims
S100A9 is a new inflammatory marker associated with obesity and cardiovascular disease. Because epicardial adipose tissue (EAT) is an inflammatory source in coronary artery disease (CAD), our aim was to evaluate the S100A9 levels in plasma and EAT and its association with CAD.Main methods
Blood, EAT and/or subcutaneous adipose tissue (SAT) biopsies were obtained from 89 patients undergoing elective cardiac surgery. Plasma S100A9 and adiponectin were analyzed by enzyme-linked immunosorbent assay (ELISA) and mRNA expression in both fat pads and were measured by real-time polymerase chain reaction (PCR).Key findings
Our results have shown higher levels of plasma S100A9 in patients with CAD than those without (29 [10–50] vs. 17 [3–28] ng/mL; p = 0.007). They were dependent on the number of injured-coronaries (p = 0.002) with tendency toward negative association with plasma adiponectin (p = 0.139). Although EAT expressed higher levels than SAT and their levels were higher in CAD patients, this last difference did not reach statistical significance. However, there was a positive correlation between neutrophils and EAT S100A9 expression (p = 0.007) that may reveal an increase of neutrophil filtration on this fat pad.Significance
Plasma S100A9 levels are increased in chronic CAD. The absence of differences regarding EAT S100A9 expression levels indicates a differential inflammatory process between fat tissues and blood in CAD process. 相似文献2.
Aims
Melatonin possesses various pharmacological effects including neuroprotective effects against brain ischemia. Post-ischemic increases in matrix metalloproteinase-9 (MMP-9) expression and activity mainly contribute to neuronal damage by degradation of the extracellular matrix. This study was designed to examine whether melatonin has a neuroprotective effect and an influence on MMP-9 in transient global brain ischemia.Main methods
Mice were subjected to 20 min of global brain ischemia and sacrificed 72 h later. Melatonin (30 mg/kg) was administered 30 min before and 2 h after ischemia as well as once daily until sacrifice.Key findings
Hippocampal pyramidal cell damage after ischemia was significantly decreased by melatonin. As observed by zymography, melatonin inhibited the increase of MMP-9 activity after ischemia. In the brain sections, the increased gelatinase activity was mainly observed in the hippocampus after ischemia and melatonin also reduced gelatinase activity. The laminin and NeuN expression levels were reduced in the hippocampal CA1 and CA2 regions after ischemia, and melatonin reduced laminin degradation and neuronal loss. A TUNEL assay demonstrated that there were TUNEL-positive cells in the hippocampus and the number of TUNEL-positive cells was significantly decreased by melatonin. There was no difference in the ischemia-induced hippocampal neuronal damage between the vehicle- and melatonin-treated groups of MMP-9 knock-out mice.Significance
These data demonstrate that melatonin suppressed the occurrence of neuronal injury, which might be partly due to its inhibitory effects on MMP-9 in addition to its anti-oxidative effects. MMP-9 may be an important key target of melatonin in neuroprotection against global ischemia. 相似文献3.
Bennett L. Ibey Andrei G. Pakhomov Betsy W. Gregory Vera A. Khorokhorina Caleb C. Roth Mikhail A. Rassokhin Joshua A. Bernhard Gerald J. Wilmink Olga N. Pakhomova 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Nanosecond electric pulses (EP) disrupt cell membrane and organelles and cause cell death in a manner different from the conventional irreversible electroporation. We explored the cytotoxic effect of 10-ns EP (quantitation, mechanisms, efficiency, and specificity) in comparison with 300-ns, 1.8- and 9-μs EP.Methods
Effects in Jurkat and U937 cells were characterized by survival assays, DNA electrophoresis and flow cytometry.Results
10-ns EP caused apoptotic or necrotic death within 2–20 h. Survival (S, %) followed the absorbed dose (D, J/g) as: S = αD(−K), where coefficients K and α determined the slope and the “shoulder” of the survival curve. K was similar in all groups, whereas α was cell type- and pulse duration-dependent. Long pulses caused immediate propidium uptake and phosphatidylserine (PS) externalization, whereas 10-ns pulses caused PS externalization only.Conclusions
1.8- and 9-μs EP cause cell death efficiently and indiscriminately (LD50 1–3 J/g in both cell lines); 10-ns EP are less efficient, but very selective (LD50 50–80 J/g for Jurkat and 400–500 J/g for U937); 300-ns EP show intermediate effects. Shorter EP open propidium-impermeable, small membrane pores (”nanopores”), triggering different cell death mechanisms.General significance
Nanosecond EP can selectively target certain cells in medical applications like tumor ablation. 相似文献4.
Aim
Aquaporin-4(AQP4) expression in the brain with relation to edema formation following focal cerebral ischemia was investigated. Studies have shown that brain edema is one of the significant factors in worsening stroke outcomes. While many mechanisms may aggravate brain injury, one such potential system may involve AQP4 up regulation in stroke patients that could result in increased edema formation. Post administration of melatonin following ischemic stroke reduces AQP4 mediated brain edema and confers neuroprotection.Materials and methods
An in-silico approach was undertaken to confirm effective melatonin-AQP4 binding. Rats were treated with 5 mg/kg, i.p. melatonin or placebo at 30 min prior, 60 min post and 120 min post 60 min of middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion. Rats were evaluated for battery of neurological and motor function tests just before sacrifice. Brains were harvested for infarct size estimation, water content measurement, biochemical analysis, apoptosis study and western blot experiments.Key findings
Melatonin at 60 min post ischemia rendered neuroprotection as evident by reduction in cerebral infarct volume, improvement in motor and neurological deficit and reduction in brain edema. Furthermore, ischemia induced surge in levels of nitrite and malondialdehyde (MDA) were also found to be significantly reduced in ischemic brain regions in treated animals. Melatonin potentiated intrinsic antioxidant status, inhibited acid mediated rise in intracellular calcium levels, decreased apoptotic cell death and also markedly inhibited protein kinase C (PKC) influenced AQP4 expression in the cerebral cortex and dorsal striatum.Significance
Melatonin confers neuroprotection by protein kinase C mediated AQP4 inhibition in ischemic stroke. 相似文献5.
Background
Dopamine neurons derived from induced pluripotent stem cells have been widely studied for the treatment of Parkinson's disease. However, various difficulties remain to be overcome, such as tumor formation, fragility of dopamine neurons, difficulty in handling large numbers of dopamine neurons, and immune reactions. In this study, human induced pluripotent stem cell-derived precursors of dopamine neurons were encapsulated in agarose microbeads. Dopamine neurons in microbeads could be handled without specific protocols, because the microbeads protected the fragile dopamine neurons from mechanical stress.Methods
hiPS cells were seeded on a Matrigel-coated dish and cultured to induce differentiation into a dopamine neuronal linage. On day 18 of culture, cells were collected from the culture dishes and seeded into U-bottom 96-well plates to induce cell aggregate formation. After 5 days, cell aggregates were collected from the plates and microencapsulated in agarose microbeads. The microencapsulated aggregates were cultured for an additional 45 days to induce maturation of dopamine neurons.Results
Approximately 60% of all cells differentiated into tyrosine hydroxylase-positive neurons in agarose microbeads. The cells released dopamine for more than 40 days. In addition, microbeads containing cells could be cryopreserved.Conclusion
hiPS cells were successfully differentiated into dopamine neurons in agarose microbeads.General significance
Agarose microencapsulation provides a good supporting environment for the preparation and storage of dopamine neurons. 相似文献6.
7.
Jean R. Starkey Elizabeth M. Pascucci Mikhail A. Drobizhev Aleisha Elliott Aleksander K. Rebane 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Broader clinical acceptance of photodynamic therapy is currently hindered by (a) poor depth efficacy, and (b) predisposition towards establishment of an angiogenic environment during the treatment. Improved depth efficacy is being sought by exploiting the NIR tissue transparency window and by photo-activation using two-photon absorption (2PA). Here, we use two-photon activation of PDT sensitizers, untargeted and targeted to SST2 receptors or EGF receptors, to achieve deep tissue treatment.Methods
Human tumor lines, positive or negative for SST2r expression were used, as well as murine 3LL cells and bovine aortic endothelial cells. Expression of SST2 receptors on cancer cells and tumor vasculature was evaluated in vitro and frozen xenograft sections. PDT effects on tumor blood flow were followed using in vivo scanning after intravenous injection of FITC conjugated dextran 150 K. Dependence of the PDT efficacy on the laser pulse duration was evaluated. Effectiveness of targeting to vascular SST2 receptors was compared to that of EGF receptors, or no targeting.Results
Tumor vasculature stained for SST2 receptors even in tumors from SST2 receptor negative cell lines, and SST2r targeted PDT led to tumor vascular shutdown. Stretching the pulse from ~ 120 fs to ~ 3 ps led to loss of the PDT efficacy especially at greater depth. PDT targeted to SST2 receptors was much more effective than untargeted PDT or PDT targeted to EGF receptors.General significance
The use of octreotate to target SST2 receptors expressed on tumor vessels is an excellent approach to PDT with few recurrences and some long term cures. 相似文献8.
Adriana G. Guimarães Luciana Scotti Marcus Tullius Scotti Francisco J.B. Mendonça Júnior Nayara S.R. Melo Rafael S. Alves Waldecy De Lucca Júnior Daniel P. Bezerra Daniel P. Gelain Lucindo J. Quintans Júnior 《Life sciences》2014
Aims
The present study evaluated the carvacrol (CARV) effect on hyperalgesia and nociception induced by sarcoma 180 (S180) in mice.Main methods
Carvacrol treatment (12.5–50 mg/kg s.c.) once daily for 15 days was started 24 h after injection of the sarcoma cells in the hind paw (s.c.). Mice were evaluated for mechanical sensitivity (von Frey), spontaneous and palpation-induced nociception, limb use and tumor growth on alternate days. CARV effects on the central nervous system were evaluated through immunofluorescence for Fos protein. Molecular docking studies also were performed to evaluate intermolecular interactions of the carvacrol and muscimol, as ligands of interleukin-10 and GABAA receptors.Key findings
CARV was able to significantly reduce mechanical hyperalgesia and spontaneous and palpation-induced nociception, improve use paw, decrease the number of positively marked neurons in lumbar spinal cord and activate periaqueductal gray, nucleus raphe magnus and locus coeruleus. CARV also caused significant decreased tumor growth. Docking studies showed favorable interaction overlay of the CARV with IL-10 and GABAA.Significance
Together, these results demonstrated that CARV may be an interesting option for the development of new analgesic drugs for the management of cancer pain. 相似文献9.
Aims
Activation of retinal microglial cells (RMCs) is known to contribute to retinal ganglion cell (RGC) death after optic nerve injury. The purpose of this study was to investigate the effects of intravenous injection of α-crystallin on RGC survival and RMC activation in a rat model of optic nerve crush.Main methods
RGCs were retrogradely labeled with fluorogold. Rats were intravenously injected with normal saline or α-crystallin (0.05 g/kg, 0.5 g/kg, and 5 g/kg) at 2, 4, 6, 8, 10, and 12 days after the optic nerve crush. Activated RMCs were characterized using immunofluorescence labeling with CD11b, and TNF-α and iNOS expression was detected using immunoblot analyses. We analyzed the morphology and numbers of RGC and RMC 2 and 4 weeks after injury using fluorescence and confocal microscopy.Key findings
The number of RGCs decreased after optic nerve injury, accompanied by significantly increased numbers of activated RMCs. Intravenous injection of α-crystallin decreased the number of RMCs, and enhanced the number of RGCs compared to saline injection. α-Crystallin administration inhibited TNF-α and iNOS protein expression induced by optic nerve injury.Significance
Our results suggest that α-crystallin promotes RGC survival and inhibits RMC activation. Intravenous injection of α-crystallin could be a possible strategy for the treatment of optic nerve injury. 相似文献10.
Roberta Cotugno Dario Gallotta Fabrizio Dal Piaz Ivana Apicella Sandro De Falco Sergio Rosselli Maurizio Bruno Maria Antonietta Belisario 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
The semi-synthetic ent-kaurane 15-ketoatractyligenin methyl ester (SC2017) has been previously reported to possess high antiproliferative activity against several solid tumor-derived cell lines. Our study was aimed at investigating SC2017 tumor growth-inhibiting activity and the underlying mechanisms in Jurkat cells (T-cell leukemia) and xenograft tumor models.Methods
Cell viability was evaluated by MTT assay. Cell cycle progression, reactive oxygen species (ROS) elevation and apoptotic hallmarks were monitored by flow cytometry. Inhibition of thioredoxin reductase (TrxR) by biochemical assays. Levels and/or activation status of signaling proteins were assessed by western blotting. Xenograft tumors were generated with HCT 116 colon carcinoma cells.Results
SC2017 displayed cell growth-inhibiting activity against Jurkat cells (half maximal inhibitory concentration values (IC50) < 2 μM), but low cell-killing potential in human peripheral blood mononuclear cells (PBMC). The primary response of Jurkat cells to SC2017 was an arrest in G2 phase followed by caspase-dependent apoptosis. Inhibition of PI3K/Akt pathway and TrxR activity by SC2017 was demonstrated by biochemical and pharmacological approaches. At least, SC2017 was found to inhibit xenograft tumor growth.Conclusions
Our results demonstrate that SC2017 inhibits tumor cell growth in in vitro and in vivo models, but displays moderate toxicity against PBMC. We also demonstrate that SC2017 promotes caspase-dependent apoptosis in Jurkat cells by affecting Akt activation status and TrxR functionality.General significance
Our observations suggest the semi-synthetic ent-kaurane SC2017 as a promising chemotherapeutic compound. SC2017 has, indeed, shown to possess tumor growth inhibiting activity and be able to counteract PI3K/Akt and Trx system survival signaling. 相似文献11.
Masahiro Endo Hidehiko Beppu Hidehiko Akiyama Kazumasa Wakamatsu Shosuke Ito Yasuko Kawamoto Kan Shimpo Toshimitu Sumiya Takaaki Koike Taei Matsui 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Mushrooms of the genus Agaricus are a common folk remedy against carcinoma. The active ingredients, polysaccharides and protein-polysaccharide complexes containing β-glucan, have been isolated and shown to have indirect tumor-suppressing activity via an immunological activation.Methods
The diffusible fraction of a hot-water extract of Agaricus blazei Murrill (ABM) powder was fractionated by HPLC based on the anti-tumor activity against leukemic cells in vitro. The structure of the anti-tumor substance was determined by NMR and MS analyses.Results
We purified a tumorcidal substance from the diffusible fraction of ABM and identified it as agaritine, β-N-(γ-l(+)-glutamyl)-4-(hydroxymethyl) phenylhydrazine, having a molecular mass of 267 Da. This compound inhibited the proliferation of leukemic cell lines such as U937, MOLT4, HL60 and K562 with IC50 values of 2.7, 9.4, 13.0, and 16.0 μg/mL, respectively, but showed no significant effect on normal lymphatic cells at concentrations up to 40 μg/mL. Although agaritine has been suspected of having genotoxic or carcinogenic properties, agaritine did not activate the umu gene of Salmonella, which reacts to carcinogens.General significance
The results indicate that agaritine from ABM has direct anti-tumor activity against leukemic tumor cells in vitro. This is in contrast to the carcinogenic activity previously ascribed to this compound. Our results also show that this activity is distinct from that of β-glucan, which indirectly suppresses proliferation of tumor cells. 相似文献12.
Aims
PTBP3 overexpression inhibits the differentiation of leukemia cells; however, its effects on the differentiation and proliferation of solid cancer cells remain unclear. Thus, the impact of PTBP3 on the differentiation and proliferation of gastric cancer cells was investigated.Main methods
PTBP3 expression was analyzed in normal and tumor tissues using immunohistochemistry. A xenograft model was established in nude mice by subcutaneous injection of untransfected human gastric cancer MKN45 cells or those expressing a control vector or PTBP3 siRNA. We analyzed the tumor inhibition rate, the expression of PTBP3, the PCNA-positive rate and the serum levels of CEA, CA199, CA125, LDH, ALP and γ-GT in different groups.Key findings
The tumor weights in the PTBP3 siRNA group were significantly lower than that of the MKN45 cell control group (P < 0.001). Immunohistochemistry analysis of PCNA expression revealed that it was markedly reduced after PTBP3 silencing. ELISAs showed that the serum levels of CEA and CA199 tumor markers as well as LDH and ALP were reduced after PTBP3 silencing. Transmission electron microscopy revealed that MKN45 cells expressing PTBP3 siRNA had reduced nuclear-to-cytoplasmic ratio and regular nuclei, suggesting differentiation.Significance
PTBP3 may promote proliferation and inhibit the differentiation of human gastric cancer MKN45 cells. 相似文献13.
Li-Chen Ge Zhuo-Jia Chen Hao Liu Kun-Shui Zhang Qiao Su Xiang-Yu Ma Hong-Bin Huang Zhen-Dong Zhao Yu-Ye Wang John P. Giesy Jun Du Hong-Sheng Wang 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Biphasic effects on cell proliferation of bisphenol A (BPA) can occur at lesser or greater exposures. Sertoli cells play a pivotal role in supporting proliferation and differentiation of germ cells. The mechanisms responsible for inverse effects of great and low concentrations of BPA on Sertoli cell proliferation need further study.Methods
We utilized proteomic study to indentify the protein expression changes of Sertoli TM4 cells treated with 10− 8 M and 10− 5 M BPA. The further mechanisms related to mitochondria, energy metabolism and oxidative stress were investigated by qRT-PCR and Western-blotting analysis.Results
Proteomic studies identified 36 proteins and two major clusters of proteins including energy metabolism and oxidative stress expressed with opposite changes in Sertoli cells treated with 10− 8 M and 10− 5 M BPA, respectively, for 24 h. Exposure to 10− 5 M BPA resulted in greater oxidative stress and then inhibited cell proliferation, while ROS scavenger NAC effectively blocked these effects. Exposure to 10− 8 M BPA caused higher intercellular ATP, greater activities of mitochondria, and resulted in significant proliferation of TM4 cells, while oligomycin A, an inhibitor of ATP synthase, abolished these growth advantages.Conclusions
Our study demonstrated that micromolar BPA inhibits proliferation of Sertoli cells by elevating oxidative stress while nanomolar BPA stimulates proliferation by promoting energy metabolism.General significance
Micromolar BPA inhibits cell proliferation by elevating oxidative stress while nanomolar BPA stimulates cell proliferation by promoting energy metabolism. 相似文献14.
Jafar Mohseni Chia Boon Hock Che Abdul Razak Syah Nor Iman Othman Fatemeh Hayati Winnie Ong PeiTee Muzhirah Haniffa Bin Alwi Zilfalil Rowani Mohd. Rawi Lock-Hock Ngu Teguh Haryo Sasongko 《Gene》2014
Background
Hyperargininemia is a very rare progressive neurometabolic disorder caused by deficiency of hepatic cytosolic arginase I, resulting from mutations in the ARG1 gene. Until now, some mutations were reported worldwide and none of them were of Southeast Asian origins. Furthermore, most reported mutations were point mutations and a few others deletions or insertions.Objective
This study aims at identifying the disease-causing mutation in the ARG1 gene of Malaysian patients with hyperargininemia.Methodology
We employed a series of PCR amplifications and direct sequencing in order to identify the mutation. We subsequently used quantitative real-time PCR to determine the copy number of the exons flanking the mutation. We blasted our sequencing data with that of the reference sequence in the NCBI in order to obtain positional insights of the mutation.Results
We found a novel complex re-arrangement involving insertion, inversion and gross deletion of ARG1 (designated g.insIVS1 + 1899GTTTTATCAT;g.invIVS1 + 1933_ + 1953;g.delIVS1 + 1954_IVS2 + 914;c.del116_188;p.Pro20SerfsX4) commonly shared by 5 patients with hyperargininemia, each originating from different family. None of the affected families share known relationship with each other, although four of the five patients were known to have first-cousin consanguineous parents.Conclusion
This is the first report of complex re-arrangement in the ARG1. Further analyses showing that the patients have shared the same geographic origin within the northeastern part of Malaysia prompted us to suggest a simple molecular screening of hyperargininemia within related ethnicities using a long-range PCR. 相似文献15.
Objective
The purpose of this study was to evaluate the feasibility, safety, and efficacy of cryoablation to treat pain from paravertebral malignant mesenchymal tumors.Method
Cryoablation was performed on 15 patients who suffer from unresectable painful paravertebral malignant mesenchymal tumors and whose pain was poorly controlled by conventional treatment methods. The sizes of the tumors varied from 3 to 20 cm. The patients’ pain at baseline before the cryoablation and the pain they felt 1 day, 1 week, 1 month, and 3 months after the cryoablation were assessed respectively by the Brief Pain Inventory (BPI).Result
BPI scores are divided into two categories: the influence of pain and the severity of pain. Both results showed a decline after the cryoablation. The evaluation score of pain severity decreased significantly (P = 0.001, P = 0.031) on the observation of 1 day and 1 month after the cryoablation; that of pain influence decreased significantly (P = 0.016, P = 0.036) in the cases of 1 day and 1 week after cryoablation. Two patients (13.33%) had mild complications, but no serious complications occurred.Conclusion
Cryoablation is a low risk, well-tolerated topical treatment for the pain of patients with unresectable paravertebral malignant mesenchymal tumor. 相似文献16.
Giuseppe Maulucci Diana Troiani Sara Letizia Maria Eramo Fabiola Paciello Maria Vittoria Podda Gaetano Paludetti Massimiliano Papi Alessandro Maiorana Valentina Palmieri Marco De Spirito Anna Rita Fetoni 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Noise exposure impairs outer hair cells (OHCs). The common basis for OHC dysfunction and loss by acoustic over-stimulation is represented by reactive oxygen species (ROS) overload that may affect the membrane structural organization through generation of lipid peroxidation.Methods
Here we investigated in OHC different functional zones the mechanisms linking metabolic functional state (NAD(P)H intracellular distribution) to the generation of lipid peroxides and to the physical state of membranes by two photon fluorescence microscopy.Results
In OHCs of control animals, a more oxidized NAD(P)H redox state is associated to a less fluid plasma membrane structure. Acoustic trauma induces a topologically differentiated NAD(P)H oxidation in OHC rows, which is damped between 1 and 6 h. Peroxidation occurs after ~ 4 h from noise insult, while ROS are produced in the first 0.2 h and damage cells for a period of time after noise exposure has ended (~ 7.5 h) when a decrease of fluidity of OHC plasma membrane occurs. OHCs belonging to inner rows, characterized by a lower metabolic activity with respect to other rows, show less severe metabolic impairment.Conclusions
Our data indicate that plasma membrane fluidity is related to NAD(P)H redox state and lipid peroxidation in hair cells.General Significance
Our results could pave the way for therapeutic intervention targeting the onset of redox umbalance. 相似文献17.
Aim
This study aimed to examine the causal relationship between adipokines released from visceral fat and pancreatic β-cell dysfunction in the state of obesity inflammation.Main methods
Adipose tissue and adipocyte conditioned medium were obtained from epididymal fat of B6 mice on regular or high fat diet for 16 weeks. The latter were classified into two groups: overweight (OW, 40 ± 2 g) and obese (OB, 50 ± 2 g). Isolated mouse islets and NIT-1 cells were used to evaluate β-cell function.Key findings
Fasting glucose, leptin, and interleukin-6 levels were increased in OW mice and were further elevated in OB mice. Adipocyte size and number of adipose macrophage infiltrations showed a similar trend. The augmentation of homeostasis model assessment of insulin resistance, islet hyperplasia and macrophage infiltration was noted only in OB mice. The stimulation index was lower, but reactive oxygen species production was higher in islets isolated from OB mice than from controls. In epididymal fat conditioned medium, the increases in leptin, IL-6 and TNF-α production in OW mice were further elevated in OB mice except TNF-α. Adipose tissue conditioned medium suppressed the stimulation index of islets isolated from B6 mice but not from db/db mice. The suppressive effect was also reversed by co-treatment with N-acetylcysteine or NS-398 (a selective cyclooxygenase-2 inhibitor).Significance
A markedly elevated leptin production from inflamed visceral fat could deteriorate β-cell function via leptin receptor-mediated oxidative stress and cyclooxygenase-2 activation in the development of obesity. 相似文献18.
M.C. Ribeiro M.S. Costa-Alves M. Wengert J.R. Meyer-Fernandes P. Zancan C. Caruso-Neves A.A.S. Pinheiro 《Biochimica et Biophysica Acta (BBA)/General Subjects》2012
Background
The concentration of extracellular nucleotides is regulated by enzymes that have their catalytic site facing the extracellular space, the so-called ecto-enzymes.Methods
We used LLC-PK1 cells, a well-characterized porcine renal proximal tubule cell line, to biochemically characterize ecto-ATPase activity in the luminal surface. The [γ-32P]Pi released after reaction was measured in aliquots of the supernatant by liquid scintillation.Results
This activity was linear with time up to 20 min of reaction and stimulated by divalent metals. The ecto-ATPase activity measured in the presence of 5 mM MgCl2 was (1) optimum at pH 8, (2) insensitive to different inhibitors of intracellular ATPases, (3) inhibited by 1 mM suramin, an inhibitor of ecto-ATPases, (4) sensitive to high concentrations of sodium azide (NaN3) and (5) also able to hydrolyze ADP in the extracellular medium. The ATP:ADP hydrolysis ratio calculated was 4:1. The ecto-ADPase activity was also inhibited by suramin and NaN3. The dose–response of ATP revealed a hyperbolic profile with maximal velocity of 25.2 ± 1.2 nmol Pi x mg− 1 x min− 1 and K0.5 of 0.07 ± 0.01 mM. When cells were submitted to ischemia, the E-NTPDase activity was reduced with time, achieving 71% inhibition at 60 min of ischemia.Conclusion
Our results suggest that the ecto-ATPase activity of LLC-PK1 cells has the characteristics of a type 3 E-NTPDase which is inhibited by ischemia.General Significance
This could represent an important pathophysiologic mechanism that explains the increase in ATP concentration in the extracellular milieu in the proximal tubule during ischemia. 相似文献19.
Gunjan Tyagi Shrikant Pradhan Tapasya Srivastava Ranjana Mehrotra 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Allicin has received much attention due to its anti-proliferative activity and not-well elucidated underlying mechanism of action. This work focuses towards determining the cellular toxicity of allicin and understanding its interaction with nucleic acid at molecular level.Methods
MTT assay was used to assess the cell viability of A549 lung cancer cells against allicin. Fourier transform infrared (FTIR) and UV-visible spectroscopy were used to study the binding parameters of nucleic acid-allicin interaction.Results
Allicin inhibits the proliferation of cancer cells in a concentration dependent manner. FTIR spectroscopy exhibited that allicin binds preferentially to minor groove of DNA via thymine base. Analysis of tRNA allicin complex has also revealed that allicin binds primarily through nitrogenous bases. Some amount of external binding with phosphate backbone was also observed for both DNA and RNA. UV visible spectra of both DNA allicin and RNA allicin complexes showed hypochromic shift with an estimated binding constant of 1.2 × 104 M- 1 for DNA and 1.06 × 103 M− 1for RNA binding. No major transition from the B-form of DNA and A-form of RNA is observed after their interaction with allicin.Conclusions
The results demonstrated that allicin treatment inhibited the proliferation of A549 cells in a dose-dependent manner. Biophysical outcomes are suggestive of base binding and helix contraction of nucleic acid structure upon binding with allicin.General significance
The results describe cytotoxic potential of allicin and its binding properties with cellular nucleic acid, which could be helpful in deciphering the complete mechanism of cell death exerted by allicin. 相似文献20.
Élodie Breton Christian Goetz Jacqueline Kintz Nathalie Accart Gaëlle Aubertin Bernard Grellier Philippe Erbs Ronald Rooke André Constantinesco Philippe Choquet 《Comptes rendus biologies》2010,333(3):220-225